I suppose I am trying to say that if the professionals are at all, well, professional, then they are asking as this is a factor relevant to the diagnostic procedure and not to "blame" the parent for how the child is presenting.
I am worried that people are talking about lying and omitting this information for fear that it will prevent their child getting a diagnosis. I can tell you thatin my experience, there have been very many more parents who reported depression whose children obtained diagnoses than those who did not receive a diagnosis because of this one factor. A proper diagnostic procedure should involve a whole team of professionals to consider the child holistically to avoid situations like Al1son described where one factor is seized upon as a "yay" or "nay" immediately.
I know that, sadly, there are rubbish professionals like Al1sons's out there.. but this is no reason to lie or to omit relevant information, as there are rubbish professionals in every field in terms of healthcare. I can't say it enough: depression is not a parenting fault, it is an illness and it may be an important piece of information in determining diagnosis.
I know it is rubbish that the system is as shoddy as it is and that people feel that they can't have faith in it.. but to be pragmatic about it, I think that deciding to leave this out can backfire e.g. it can lead to a parent painting a too rosey picture of early infancy which (in my experience) is far more often considered evidence that a diagnosis may not be appropriate e.g. "oh my baby and I bonded fantastically from day one and he was very responsive and cooing and gurgling and full of fun until he was eighteen months". I am not specifically talking about stories of regression here, but an inconsistent picture e.g. the "story" that is told about early infancy just doesn't match up with that child at 1, 2 or 3. I will say that I have found that sometimes in desperation at the crapness of it all that parents come in reeling off lists of symptoms that are sometimes even contradictory because they just want to "press the right buttons" because they are absolutely worn out from trying to get to that point and feel that they have to prove their case or else face an eternity with no support.
The sad reality is that this is much more likely to cause a team to query a diagnosis than, well, the actual truth. It can be very confusing when you're trying to wade through information to make a diagnosis and a lot of it seems to be worded as though it were a DSM-IV manual instead of as a parent telling you about their child.
I fully appreciate the reasons why this happens and that it is our fault as professionals and the fault of the slow, clunky system which is inadequate in so many regards.. but I would urge people to be honest because an honest case history combined with the relevant assessments and a proper multidisciplinary process should be sufficient to obtain a diagnosis if that diagnosis is accurate for that child at that time. If the result is not what you feel to be true about your child, then you can challenge the rationale and unpick it and demand that the reason for the decision is discussed in detail with you to aid this e.g. fight when you have to when it comes to diagnosis, rather than trying to "cut them off at the pass" when it might not be something that helps obtain a favourable outcome anyway.
Hope this makes sense?